As the wireless charging technology matures and the charging efficiency improves, more portable electronic devices, such as, mobile phone, personal video player, digital camera, and so on, use wireless charging. The above electronic devices use a built-in receiving induction coil electrically connected to the battery, and a wireless charging apparatus is disposed with a built-in transmitting induction coil. When the transmitting and the receiving induction coils get close, the energy can be propagated according to the electromagnetic effect and electromagnetic resonance effect. After the electricity power transformation, the battery of the electronic device can be charged.
The conventional wireless charging apparatus often includes a power cord and a wireless charging pad. The wireless charging pad is for placing a wirelessly chargeable electronic device upon, and the power cord can be plugged into a socket through the plug at the end of the power cord. As such, the charging is performed through electromagnetic effect. Although convenient, the charging often must be conducted on a flat surface, such as a desk top, or some stable places devoid of shaking or swinging. Such wireless charging apparatus is often unsuitable for a mobile phone to stand in a tilt position or charging inside a moving vehicle. Therefore, the convenience issue must be re-addressed.